It’s easy to forget just how revolutionary the Mac was when it was first introduced. For my part, I’ll never forget the first time I saw a Mac, because I was dumbstruck. It was as if I had been hit by a bolt of lightning.

I grew up in the 1970s in the era of “latchkey kids”—the then-nascent and still somewhat unusual phenomenon of children who returned to an empty house after school. I was the only child of a working single mother, who was always looking for stuff to keep me busy. She was concerned about a lack of adult male role models in my life, so she enrolled me in the Big Brother program. The organization paired boys like me with an adult male who would hopefully impart some valuable life lessons and friendship along the way.

In the summer of 1978, my Big Brother, Ron, introduced me to my first personal computer. Ron was a systems analyst at a telecommunications company, and had once brought me to his office where I first saw massive mainframes that took up entire rooms. This was just like one of those massive machines, but it sat on a desktop in his home office.

Ron’s new toy was a TRS-80 Model I, and it was amazing. A grey keyboard with a black top and heavy mechanical keys, connected to a separate black-and-white display molded from the same grey plastic.

I sat down in front of it and saw a flashing cursor on the screen.

“What can it do?” I asked him.

“Anything you want,” he replied.

“Can it play games?” I asked.

“Sure. You just have to write them first.”

Thus began my introduction to personal computing. Ron taught me BASIC, the computer language built into the computer, and that summer I ended up writing—with his help, of course—a simple arithmetic game with blocky spaceship graphics. It wasn’t Pong, like I’d played at my friend’s house, but it was cool. Because I understood how it worked.

By the early 1980s, I’d gotten my own computer—a TI-99/4A. For a while, I was content to buy games on cartridges that went into a slot, but by the summer of 1984, we’d invested in an expansion chassis that included a floppy disk drive and additional memory.

I could buy games on cartridge, but as a 14-year-old, I didn’t have a lot of disposable income. So I preferred to pick up copies of computer hobbyist magazines, which had programs printed out in the back. I was particularly fond of transcribing the games I’d find there—text adventures, arcade games, puzzles.

By then I was experimenting with my own bitmapped graphics. I learned that I could display imagery of my own creation using BASIC and by printing strings of data to the screen. I’d draw out an image that I wanted on a piece of graph paper, then divide that graph paper into quadrants eight rows long and eight columns wide. I could then figure out—based on which squares were darkened and which were empty—what their hexadecimal value was. Entering that as a data string in a simple BASIC program I’d written would display an image on screen.